As is known in the art, tomosynthesis is a technique for acquiring and processing a series of projection measurements of an object into three dimensional (3D) slice information. In breast tomosynthesis, for example, the breast is held immobile, while a source (such as an X-ray tube) and/or the detector are moved through a series of positions on an arc to generate a sequence of projection measurements (exposures) at different view-angles. Moving the radiation source through an arc requires motorized translational control of a relatively heavy X-ray tube and gantry assembly to generate the projection images. This is generally cumbersome and tends to induce vibrations in the apparatus being moved. The vibrations reduce the ability of the system to image relatively small features of an object.